Commit | Line | Data |
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2fe58dfd SE |
1 | /* UDP send/receive module for secnet */ |
2 | ||
3 | /* This module enables sites to communicate by sending UDP | |
4 | * packets. When an instance of the module is created we can | |
5 | * optionally bind to a particular local IP address (not implemented | |
6 | * yet). | |
7 | * | |
2fe58dfd SE |
8 | * Packets are offered to registered receivers in turn. Once one |
9 | * accepts it, it isn't offered to any more. */ | |
10 | ||
8689b3a9 | 11 | #include "secnet.h" |
2fe58dfd SE |
12 | #include <stdio.h> |
13 | #include <unistd.h> | |
14 | #include <fcntl.h> | |
15 | #include <string.h> | |
16 | #include <errno.h> | |
2fe58dfd | 17 | #include <sys/socket.h> |
b2a56f7c | 18 | #include <sys/wait.h> |
5edf478f IJ |
19 | #include <netinet/in.h> |
20 | #include <arpa/inet.h> | |
2fe58dfd | 21 | #include "util.h" |
dd9209d1 | 22 | #include "magic.h" |
794f2398 | 23 | #include "unaligned.h" |
ff05a229 | 24 | #include "ipaddr.h" |
136740e6 | 25 | #include "magic.h" |
54d5ef00 | 26 | #include "comm-common.h" |
2fe58dfd SE |
27 | |
28 | static beforepoll_fn udp_beforepoll; | |
29 | static afterpoll_fn udp_afterpoll; | |
2fe58dfd SE |
30 | static comm_sendmsg_fn udp_sendmsg; |
31 | ||
7d31df0e | 32 | #define UDP_MAX_SOCKETS 3 /* 2 ought to do really */ |
08b62a6c IJ |
33 | |
34 | struct udpsock { | |
35 | union iaddr addr; | |
36 | int fd; | |
37 | }; | |
38 | ||
2fe58dfd | 39 | struct udp { |
54d5ef00 | 40 | struct commcommon cc; |
08b62a6c | 41 | int n_socks; |
7d31df0e | 42 | struct udpsock socks[UDP_MAX_SOCKETS]; |
b2a56f7c | 43 | string_t authbind; |
ff05a229 | 44 | bool_t use_proxy; |
a32d56fb | 45 | union iaddr proxy; |
2fe58dfd SE |
46 | }; |
47 | ||
08b62a6c IJ |
48 | /* |
49 | * Re comm_addr.ix: This field allows us to note in the comm_addr | |
50 | * which socket an incoming packet was received on. This is required | |
51 | * for conveniently logging the actual source of a packet. But the ix | |
52 | * does not formally form part of the address: it is not used when | |
53 | * sending, nor when comparing two comm_addrs. | |
54 | * | |
55 | * The special value -1 means that the comm_addr was constructed by | |
56 | * another module in secnet (eg the resolver), rather than being a | |
57 | * description of the source of an incoming packet. | |
58 | */ | |
59 | ||
54d5ef00 IJ |
60 | static const char *udp_addr_to_string(void *commst, const struct comm_addr *ca) |
61 | { | |
5edf478f | 62 | struct udp *st=commst; |
7d31df0e | 63 | struct udp *socks=st; /* for now */ |
5edf478f | 64 | static char sbuf[100]; |
08b62a6c | 65 | int ix=ca->ix>=0 ? ca->ix : 0; |
5edf478f | 66 | |
7d31df0e | 67 | assert(ix>=0 && ix<socks->n_socks); |
08b62a6c | 68 | snprintf(sbuf, sizeof(sbuf), "udp:%s%s-%s", |
7d31df0e | 69 | iaddr_to_string(&socks->socks[ix].addr), |
08b62a6c IJ |
70 | ca->ix<0 ? "&" : "", |
71 | iaddr_to_string(&ca->ia)); | |
5edf478f IJ |
72 | return sbuf; |
73 | } | |
74 | ||
2fe58dfd | 75 | static int udp_beforepoll(void *state, struct pollfd *fds, int *nfds_io, |
90a39563 | 76 | int *timeout_io) |
2fe58dfd | 77 | { |
08b62a6c | 78 | int i; |
2fe58dfd | 79 | struct udp *st=state; |
7d31df0e IJ |
80 | struct udp *socks=st; /* for now */ |
81 | BEFOREPOLL_WANT_FDS(socks->n_socks); | |
82 | for (i=0; i<socks->n_socks; i++) { | |
83 | fds[i].fd=socks->socks[i].fd; | |
08b62a6c IJ |
84 | fds[i].events=POLLIN; |
85 | } | |
2fe58dfd SE |
86 | return 0; |
87 | } | |
88 | ||
90a39563 | 89 | static void udp_afterpoll(void *state, struct pollfd *fds, int nfds) |
2fe58dfd SE |
90 | { |
91 | struct udp *st=state; | |
54d5ef00 | 92 | struct commcommon *cc=&st->cc; |
7d31df0e | 93 | struct udp *socks=st; /* for now */ |
7d31df0e | 94 | struct udp *uc=st; /* for now */ |
a32d56fb | 95 | union iaddr from; |
b1a0f651 | 96 | socklen_t fromlen; |
2fe58dfd SE |
97 | bool_t done; |
98 | int rv; | |
08b62a6c | 99 | int i; |
2fe58dfd | 100 | |
08b62a6c IJ |
101 | for (i=0; i<st->n_socks; i++) { |
102 | if (i>=nfds) continue; | |
103 | if (!(fds[i].revents & POLLIN)) continue; | |
7d31df0e IJ |
104 | assert(fds[i].fd == socks->socks[i].fd); |
105 | int fd=socks->socks[i].fd; | |
2fe58dfd SE |
106 | do { |
107 | fromlen=sizeof(from); | |
7d31df0e IJ |
108 | BUF_ASSERT_FREE(cc->rbuf); |
109 | BUF_ALLOC(cc->rbuf,"udp_afterpoll"); | |
110 | buffer_init(cc->rbuf,calculate_max_start_pad()); | |
111 | rv=recvfrom(fd, cc->rbuf->start, | |
112 | buf_remaining_space(cc->rbuf), | |
a32d56fb | 113 | 0, &from.sa, &fromlen); |
2fe58dfd | 114 | if (rv>0) { |
7d31df0e IJ |
115 | cc->rbuf->size=rv; |
116 | if (uc->use_proxy) { | |
ff05a229 SE |
117 | /* Check that the packet came from our poxy server; |
118 | we shouldn't be contacted directly by anybody else | |
119 | (since they can trivially forge source addresses) */ | |
7d31df0e | 120 | if (!iaddr_equal(&from,&uc->proxy)) { |
ff05a229 SE |
121 | Message(M_INFO,"udp: received packet that's not " |
122 | "from the proxy\n"); | |
7d31df0e | 123 | BUF_FREE(cc->rbuf); |
ff05a229 SE |
124 | continue; |
125 | } | |
a32d56fb IJ |
126 | /* proxy protocol supports ipv4 transport only */ |
127 | from.sa.sa_family=AF_INET; | |
c1ddd026 | 128 | BUF_GET_BYTES(unprepend,cc->rbuf,&from.sin.sin_addr,4); |
7d31df0e | 129 | buf_unprepend(cc->rbuf,2); |
c1ddd026 | 130 | BUF_GET_BYTES(unprepend,cc->rbuf,&from.sin.sin_port,2); |
ff05a229 | 131 | } |
8534d602 | 132 | struct comm_addr ca; |
7d31df0e | 133 | ca.comm=&cc->ops; |
a32d56fb | 134 | ca.ia=from; |
08b62a6c | 135 | ca.ix=i; |
54d5ef00 | 136 | done=comm_notify(&cc->notify, cc->rbuf, &ca); |
2fe58dfd | 137 | if (!done) { |
bf28fc73 | 138 | uint32_t msgtype; |
7d31df0e IJ |
139 | if (cc->rbuf->size>12 /* prevents traffic amplification */ |
140 | && ((msgtype=get_uint32(cc->rbuf->start+8)) | |
bf28fc73 IJ |
141 | != LABEL_NAK)) { |
142 | uint32_t source,dest; | |
143 | /* Manufacture and send NAK packet */ | |
7d31df0e IJ |
144 | source=get_uint32(cc->rbuf->start); /* Us */ |
145 | dest=get_uint32(cc->rbuf->start+4); /* Them */ | |
146 | send_nak(&ca,source,dest,msgtype,cc->rbuf,"unwanted"); | |
bf28fc73 | 147 | } |
7d31df0e | 148 | BUF_FREE(cc->rbuf); |
2fe58dfd | 149 | } |
7d31df0e | 150 | BUF_ASSERT_FREE(cc->rbuf); |
2fe58dfd | 151 | } else { |
7d31df0e | 152 | BUF_FREE(cc->rbuf); |
2fe58dfd SE |
153 | } |
154 | } while (rv>=0); | |
155 | } | |
156 | } | |
157 | ||
2fe58dfd | 158 | static bool_t udp_sendmsg(void *commst, struct buffer_if *buf, |
a15faeb2 | 159 | const struct comm_addr *dest) |
2fe58dfd SE |
160 | { |
161 | struct udp *st=commst; | |
7d31df0e IJ |
162 | struct udp *uc=st; /* for now */ |
163 | struct udp *socks=st; /* for now */ | |
ff05a229 | 164 | uint8_t *sa; |
2fe58dfd | 165 | |
7d31df0e | 166 | if (uc->use_proxy) { |
3abd18e8 | 167 | sa=buf_prepend(buf,8); |
a32d56fb IJ |
168 | if (dest->ia.sa.sa_family != AF_INET) { |
169 | Message(M_INFO, | |
170 | "udp: proxy means dropping outgoing non-IPv4 packet to %s\n", | |
171 | iaddr_to_string(&dest->ia)); | |
172 | return False; | |
173 | } | |
174 | memcpy(sa,&dest->ia.sin.sin_addr,4); | |
ff05a229 | 175 | memset(sa+4,0,4); |
a32d56fb | 176 | memcpy(sa+6,&dest->ia.sin.sin_port,2); |
7d31df0e IJ |
177 | sendto(socks->socks[0].fd,sa,buf->size+8,0,&uc->proxy.sa, |
178 | iaddr_socklen(&uc->proxy)); | |
3abd18e8 | 179 | buf_unprepend(buf,8); |
ff05a229 | 180 | } else { |
08b62a6c IJ |
181 | int i,r; |
182 | bool_t allunsupported=True; | |
7d31df0e IJ |
183 | for (i=0; i<socks->n_socks; i++) { |
184 | if (dest->ia.sa.sa_family != socks->socks[i].addr.sa.sa_family) | |
08b62a6c IJ |
185 | /* no point even trying */ |
186 | continue; | |
7d31df0e | 187 | r=sendto(socks->socks[i].fd, buf->start, buf->size, 0, |
08b62a6c IJ |
188 | &dest->ia.sa, iaddr_socklen(&dest->ia)); |
189 | if (r>=0) return True; | |
190 | if (!(errno==EAFNOSUPPORT || errno==ENETUNREACH)) | |
191 | /* who knows what that error means? */ | |
192 | allunsupported=False; | |
193 | } | |
194 | return !allunsupported; /* see doc for comm_sendmsg_fn in secnet.h */ | |
ff05a229 | 195 | } |
2fe58dfd SE |
196 | |
197 | return True; | |
198 | } | |
199 | ||
08b62a6c | 200 | static void udp_make_socket(struct udp *st, struct udpsock *us) |
baa06aeb | 201 | { |
f164f167 | 202 | const union iaddr *addr=&us->addr; |
54d5ef00 | 203 | struct commcommon *cc=&st->cc; /* for now */ |
7d31df0e | 204 | struct udp *uc=st; /* for now */ |
08b62a6c | 205 | us->fd=socket(addr->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP); |
f164f167 | 206 | if (us->fd<0) { |
7d31df0e | 207 | fatal_perror("udp (%s:%d): socket",cc->loc.file,cc->loc.line); |
baa06aeb | 208 | } |
f164f167 | 209 | if (fcntl(us->fd, F_SETFL, fcntl(us->fd, F_GETFL)|O_NONBLOCK)==-1) { |
baa06aeb | 210 | fatal_perror("udp (%s:%d): fcntl(set O_NONBLOCK)", |
7d31df0e | 211 | cc->loc.file,cc->loc.line); |
baa06aeb | 212 | } |
f164f167 | 213 | setcloexec(us->fd); |
08b62a6c IJ |
214 | #ifdef CONFIG_IPV6 |
215 | if (addr->sa.sa_family==AF_INET6) { | |
216 | int r; | |
217 | int optval=1; | |
218 | socklen_t optlen=sizeof(optval); | |
219 | r=setsockopt(us->fd,IPPROTO_IPV6,IPV6_V6ONLY,&optval,optlen); | |
220 | if (r) fatal_perror("udp (%s:%d): setsockopt(,IPV6_V6ONLY,&1,)", | |
7d31df0e | 221 | cc->loc.file,cc->loc.line); |
08b62a6c IJ |
222 | } |
223 | #endif | |
baa06aeb | 224 | |
7d31df0e | 225 | if (uc->authbind) { |
b2a56f7c SE |
226 | pid_t c; |
227 | int status; | |
228 | ||
229 | /* XXX this fork() and waitpid() business needs to be hidden | |
230 | in some system-specific library functions. */ | |
231 | c=fork(); | |
232 | if (c==-1) { | |
233 | fatal_perror("udp_phase_hook: fork() for authbind"); | |
234 | } | |
235 | if (c==0) { | |
3ff31eda IJ |
236 | char *argv[5], addrstr[33], portstr[5]; |
237 | const char *addrfam; | |
238 | int port; | |
f164f167 | 239 | switch (addr->sa.sa_family) { |
a32d56fb | 240 | case AF_INET: |
f164f167 | 241 | sprintf(addrstr,"%08lX",(long)addr->sin.sin_addr.s_addr); |
3ff31eda IJ |
242 | port=addr->sin.sin_port; |
243 | addrfam=NULL; | |
a32d56fb | 244 | break; |
3ff31eda IJ |
245 | #ifdef CONFIG_IPV6 |
246 | case AF_INET6: { | |
247 | int i; | |
248 | for (i=0; i<16; i++) | |
249 | sprintf(addrstr+i*2,"%02X",addr->sin6.sin6_addr.s6_addr[i]); | |
250 | port=addr->sin6.sin6_port; | |
251 | addrfam="6"; | |
252 | break; | |
253 | } | |
254 | #endif /*CONFIG_IPV6*/ | |
a32d56fb IJ |
255 | default: |
256 | fatal("udp (%s:%d): unsupported address family for authbind", | |
7d31df0e | 257 | cc->loc.file,cc->loc.line); |
a32d56fb | 258 | } |
3ff31eda | 259 | sprintf(portstr,"%04X",port); |
7d31df0e | 260 | argv[0]=uc->authbind; |
3b83c932 SE |
261 | argv[1]=addrstr; |
262 | argv[2]=portstr; | |
3ff31eda IJ |
263 | argv[3]=(char*)addrfam; |
264 | argv[4]=NULL; | |
f164f167 | 265 | dup2(us->fd,0); |
7d31df0e | 266 | execvp(uc->authbind,argv); |
3b83c932 | 267 | _exit(255); |
b2a56f7c | 268 | } |
3b83c932 SE |
269 | while (waitpid(c,&status,0)==-1) { |
270 | if (errno==EINTR) continue; | |
7d31df0e | 271 | fatal_perror("udp (%s:%d): authbind",cc->loc.file,cc->loc.line); |
b2a56f7c | 272 | } |
3b83c932 | 273 | if (WIFSIGNALED(status)) { |
7d31df0e IJ |
274 | fatal("udp (%s:%d): authbind died on signal %d",cc->loc.file, |
275 | cc->loc.line, WTERMSIG(status)); | |
3b83c932 SE |
276 | } |
277 | if (WIFEXITED(status) && WEXITSTATUS(status)!=0) { | |
7d31df0e IJ |
278 | fatal("udp (%s:%d): authbind died with status %d",cc->loc.file, |
279 | cc->loc.line, WEXITSTATUS(status)); | |
3b83c932 | 280 | } |
b2a56f7c | 281 | } else { |
08b62a6c | 282 | if (bind(us->fd, &addr->sa, iaddr_socklen(addr))!=0) { |
7d31df0e | 283 | fatal_perror("udp (%s:%d): bind",cc->loc.file,cc->loc.line); |
b2a56f7c | 284 | } |
baa06aeb | 285 | } |
f164f167 | 286 | } |
baa06aeb | 287 | |
f164f167 IJ |
288 | static void udp_phase_hook(void *sst, uint32_t new_phase) |
289 | { | |
290 | struct udp *st=sst; | |
7d31df0e | 291 | struct udp *socks=st; /* for now */ |
08b62a6c | 292 | int i; |
7d31df0e IJ |
293 | for (i=0; i<socks->n_socks; i++) |
294 | udp_make_socket(st,&socks->socks[i]); | |
08b62a6c | 295 | |
32fc582f | 296 | register_for_poll(st,udp_beforepoll,udp_afterpoll,"udp"); |
baa06aeb SE |
297 | } |
298 | ||
2fe58dfd SE |
299 | static list_t *udp_apply(closure_t *self, struct cloc loc, dict_t *context, |
300 | list_t *args) | |
301 | { | |
302 | struct udp *st; | |
08b62a6c | 303 | list_t *caddrl; |
ff05a229 SE |
304 | list_t *l; |
305 | uint32_t a; | |
08b62a6c | 306 | int i; |
2fe58dfd | 307 | |
54d5ef00 IJ |
308 | COMM_APPLY(st,&st->cc,udp_,"udp",loc); |
309 | struct commcommon *cc=&st->cc; /* for now */ | |
7d31df0e IJ |
310 | struct udp *uc=st; /* for now */ |
311 | struct udp *socks=st; /* for now */ | |
54d5ef00 | 312 | |
7d31df0e | 313 | uc->use_proxy=False; |
2fe58dfd | 314 | |
54d5ef00 | 315 | COMM_APPLY_STANDARD(st,&st->cc,"udp",args); |
2fe58dfd | 316 | |
7d31df0e | 317 | int port=dict_read_number(d,"port",True,"udp",cc->loc,0); |
08b62a6c IJ |
318 | |
319 | union iaddr defaultaddrs[] = { | |
320 | #ifdef CONFIG_IPV6 | |
321 | { .sin6 = { .sin6_family=AF_INET6, | |
322 | .sin6_port=htons(port), | |
323 | .sin6_addr=IN6ADDR_ANY_INIT } }, | |
324 | #endif | |
325 | { .sin = { .sin_family=AF_INET, | |
326 | .sin_port=htons(port), | |
327 | .sin_addr= { .s_addr=INADDR_ANY } } } | |
328 | }; | |
329 | ||
330 | caddrl=dict_lookup(d,"address"); | |
7d31df0e IJ |
331 | socks->n_socks=caddrl ? list_length(caddrl) : (int)ARRAY_SIZE(defaultaddrs); |
332 | if (socks->n_socks<=0 || socks->n_socks>UDP_MAX_SOCKETS) | |
333 | cfgfatal(cc->loc,"udp","`address' must be 1..%d addresses", | |
334 | UDP_MAX_SOCKETS); | |
08b62a6c | 335 | |
7d31df0e IJ |
336 | for (i=0; i<socks->n_socks; i++) { |
337 | struct udpsock *us=&socks->socks[i]; | |
08b62a6c IJ |
338 | if (!list_length(caddrl)) { |
339 | us->addr=defaultaddrs[i]; | |
340 | } else { | |
341 | string_item_to_iaddr(list_elem(caddrl,i),port,&us->addr,"udp"); | |
342 | } | |
343 | us->fd=-1; | |
344 | } | |
345 | ||
7d31df0e | 346 | uc->authbind=dict_read_string(d,"authbind",False,"udp",cc->loc); |
ff05a229 SE |
347 | l=dict_lookup(d,"proxy"); |
348 | if (l) { | |
7d31df0e IJ |
349 | uc->use_proxy=True; |
350 | uc->proxy.sa.sa_family=AF_INET; | |
c649eafe IJ |
351 | item=list_elem(l,0); |
352 | if (!item || item->type!=t_string) { | |
7d31df0e | 353 | cfgfatal(cc->loc,"udp","proxy must supply ""addr"",port\n"); |
ff05a229 | 354 | } |
c649eafe | 355 | a=string_item_to_ipaddr(item,"proxy"); |
7d31df0e | 356 | uc->proxy.sin.sin_addr.s_addr=htonl(a); |
c649eafe IJ |
357 | item=list_elem(l,1); |
358 | if (!item || item->type!=t_number) { | |
7d31df0e | 359 | cfgfatal(cc->loc,"udp","proxy must supply ""addr"",port\n"); |
ff05a229 | 360 | } |
7d31df0e | 361 | uc->proxy.sin.sin_port=htons(item->data.number); |
ff05a229 | 362 | } |
2fe58dfd | 363 | |
7d31df0e | 364 | update_max_start_pad(&comm_max_start_pad, uc->use_proxy ? 8 : 0); |
3abd18e8 | 365 | |
baa06aeb | 366 | add_hook(PHASE_GETRESOURCES,udp_phase_hook,st); |
2fe58dfd | 367 | |
7d31df0e | 368 | return new_closure(&cc->cl); |
2fe58dfd SE |
369 | } |
370 | ||
2fe58dfd SE |
371 | void udp_module(dict_t *dict) |
372 | { | |
373 | add_closure(dict,"udp",udp_apply); | |
374 | } |